a library that assumes spherical earth and let me divide map to squires?

I want to calculate distance between two geo coordinates but because of hardware usage (cpu, ram, database usage) I don't want to be specific instead I want to divide map to squires of my choice for example 1 Km * 1 km squires is there any library out there to do this pereferly for java-scrip language I couldn't find any
ps library to calculating distance between this two squires

If you want to slightly obfuscate the user's location, then rather than assigning them to a grid, you might effectively do the same thing by rounding off their latitudes and longitudes to however many decimal places you like then computing the distance using a more traditional Haversine Formula.

If you are still looking to move forward with the "squire" concept, then check out http://what3words.com/ as they seem to be doing something similar to what you are looking to do though perhaps at a higher level of precision and they have an API.